1. School of Information Science and Technology, Beijing Forestry University (BFU), Qinghua East Road 35, Haidian District, Beijing 100083, China
2. Engineering Research Center for Forestry-Oriented Intelligent Information Processing of National Forestry and Grassland Administration, Beijing 100083, China
3. The College of Forestry, Beijing Forestry University (BFU), Qinghua East Road 35, Haidian District, Beijing 100083, China